Genetic and epidemiological analysis of norovirus from children with gastroenteritis in Botswana, 2013–2015

Abstract

BackgroundNorovirus is a leading cause of viral gastroenteritis worldwide with a peak of disease seen in children. The epidemiological analysis regarding the virus strains in Africa is limited. The first report of norovirus in Botswana was in 2010 and currently, the prevalence and circulating genotypes of norovirus are unknown, as the country has no systems to report the norovirus cases. This study investigated the prevalence, patterns and molecular characteristics of norovirus infections among children ≤5 years of age admitted with acute gastroenteritis at four hospitals in Botswana.MethodsA total of 484 faecal samples were collected from children who were admitted with acute gastroenteritis during the rotavirus vaccine impact survey between July 2013 and December 2015. Norovirus was detected using real-time RT-PCR. Positive samples were genotyped using conventional RT-PCR followed by partial sequencing of the capsid and RdRp genes. Norovirus strains were determined by nucleotide sequence analysis using the online Norovirus Genotyping Tool Version 1.0, and confirmed using maximum likelihood tree construction as implemented in MEGA 6.0.ResultsThe prevalence of norovirus was 9.3% (95% CI 6.7–11.9). The genotype diversity was dominated by the GII.4 strain at 69.7%. This was followed by GII.2, GII.12 each at 9.1%, GI.9 at 6.6% and GII.6, GII.10 each at 3.0%. The most common combined RdRp/Capsid genotype was the GII.Pe/GII.4 Sydney 2012. Norovirus was detected during most part of the year; however, there was a preponderance of cases in the wet season (December to March).ConclusionThe study showed a possible decline of norovirus infections in the last 10 years since the first report. An upward trend seen between 2013 and 2015 may be attributable to the success of rotavirus vaccine introductions in 2012. Knowledge of circulating genotypes, seasonal trends and overall prevalence is critical for prevention programming and possible future vaccine design implications.Electronic supplementary materialThe online version of this article (10.1186/s12879-018-3157-y) contains supplementary material, which is available to authorized users.

Molecular characterization of norovirus infection responsible for acute diarrhea in Congolese hospitalized children under five years old in Brazzaville, Republic of Congo

“…The genogroup II of norovirus was found predominantly responsible for diarrhea in Congolese hospitalized children with severe diarrhea. This finding is consistent with other reports from all parts of the world confirming its high circulation (2014; Siqueira et al, 2013;Makhaola et al, 2018;Lopes de Paula et al, 2018;). This study focused on children hospitalized with severe diarrhea and it has been shown by others that genogroup I is more common in mild cases (Siqueira et al, 2017).…”

“…The present study did not identify a clear factor that could be associated significantly with norovirus infection. Others have reported human behavior, new strain variants, climate, host factors, the mode of transmission and the etiology of gastroenteritis (2013; Tang et al, 2013;Makhaola et al, 2018) as possible factors.…”

Norovirus: Facts and Reflections from Past, Present, and Future

“…Selected recent publications on the genotype distribution of human NoVs in various locations and the main variants identified, focused on both sporadic episodes and outbreaks, are detailed in Table 1. These studies differed in various aspects, such as their design (prospective, sometimes population-based, vs. retrospective analysis), age of participants, sporadic cases vs. outbreak-based studies, and/or hospitalized vs. community cases [33,34,43,[48][49][50][51][52][53][54][55][56]. Although the relative prevalence of NoV genotypes varied among studies and locations, genotype GII.4 was the most common among all studies.…”

High prevalence of norovirus and rotavirus co‐infection in children with acute gastroenteritis hospitalised in Brazzaville, Republic of Congo

“…Also they are changing from liquid to more solid food, often weaned from breastfeeding, and in regions where clean water is not always available, there could be increased exposure to contaminated food and solutions. Lastly, acquired immunity against enteric pathogens is still developing [13,25]. One interesting characteristic of the mixed RoV-NoV infection in Congolese children is the significant association with fever.…”